Yours - Su or tu ?
How do you say "Yours "
por ejemplo - Tu madre , Su madre . I see subtitles of movies where yours is said at times as "su" and at times as "tu"
Su is the Usted for of your Tu is the tú form of.
It would depend on you are talking to. A friend you say "tu madre" whereas to a stranger you would say "Su madre" . I hope this helps.
"Su madre" = your mother (formal usted)
"Tu madre" = your mother (informal)
P.s. "su madre" can also mean his/her/its mother depending on the context.